1. Field of the Invention
This invention relates to a structure for guiding tubular blanks through a sack end forming station through which the tubular blanks are transversely conveyed on a path of travel, said structure comprising two plates, which are disposed on opposite sides of said path of travel, and guiding surfaces associated with said plates and defining adjacent to said path of travel a gap which has a width that is at least as large as the thickness of the tubular blank.
2. Description of the Prior Art
In sack end forming apparatus of this kind, which are known, e.g., from Published German Application 26 39 265 and 27 43 797 and from German Utility Model Specification 74 12 879, said guiding surfaces are formed by the confronting edges of said plates, which extend across the transversely conveyed tubular blanks in the length which is required for the formation of the sack ends and define gaps having a width which is equal to the thickness of the thickest tubular blank which is to be processed. In those apparatus the width of the gaps depends on the thickness of the paper used in the tubular blanks and on the number of plies forming the walls of the tubular blank. In the operation of the known apparatus the sack ends which have been formed and passed along the gap where crimped or upset or even torn at their leading edges. The cause of the phenomenon was not known before.